fix: using t.TempDir() to simplify test temp dir manager (backport #23893)

[mergify]

Description

TempDir returns a temporary directory for the test to use.The directory is automatically removed when the test and
all its subtests complete.

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Summary by CodeRabbit

• Tests
  • Streamlined internal test processes to simplify temporary directory management, enhancing maintainability without altering user-facing functionality.

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This is an automatic backport of pull request #23893 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 159bba1 has failed:

On branch mergify/bp/release/v0.53.x/pr-23893
Your branch is up to date with 'origin/release/v0.53.x'.

You are currently cherry-picking commit 159bba145.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   x/genutil/collect_test.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   indexer/postgres/tests/init_schema_test.go
	deleted by us:   indexer/postgres/tests/postgres_test.go

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally